ABSTRACT
In this paper, we tested a hypothesis that the metal-assisted and microwave-accelerated decrystallization (MAMAD) technique, based on the combined use of low-power medical microwave heating (MWH) and gold nanoparticles (Au NPs), can be used to decrystallize laboratory-prepared monosodium urate monohydrate crystal aggregate (pseudo-tophus) placed in three-dimensional (3D) synthetic human joint models. To simulate a potential treatment of chronic tophaceous gout using the MAMAD technique, we used three different 3D synthetic human joint models and assessed the percent mass reduction (PMR, i.e., decrystallization) of pseudo-tophus and microwave-induced synthetic skin patch damage after MAMAD sessions (a MAMAD session = 120 s of MWH in the presence of Au NPs). Our three synthetic joint models are: Model 1: Application of seven MAMAD sessions in a closed synthetic joint with a pseudo-bursa containing a pseudo-tophus submerged in a solution of 20 nm Au NPs followed by dehydration of pseudo-tophus after each MAMAD session to assess PMR. Model 2: Application of seven MAMAD sessions in a closed or open synthetic joint with a pseudo-bursa containing a pseudo-tophus submerged in a solution of Au NPs followed by intermittent dehydration of pseudo-tophus after seven MAMAD sessions to assess PMR. Model 3: Application of 18 MAMAD sessions in a rotated closed synthetic joint (three sides are heated separately) with a pseudo-bursa containing a pseudo-tophus submerged in a solution of Au NPs followed by dehydration after every three MAMAD sessions to assess PMR. After a single MAMAD session, pseudo-tophus exposed to MWH and Au NPs had an average PMR of 8.30% (up to an overall PMR of 15%), and microwave-induced damage to the synthetic skin can be controlled by the use of a sacrificial skin sample and by adjusting the duration and the number of the MAMAD sessions. Computational electromagnetic simulations predict a 10% absorption of electric field by the pseudo-tophus placed in the synthetic joint models, which led us to conclude that a medical microwave source with higher power than 20 W can potentially be used with the MAMAD technique.
ABSTRACT
Background. Sexual transmission of hepatitis C virus (HCV) among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) is an emerging issue. Studies addressing the temporal trends and risk factors associated with incident HCV in HIV-infected MSM in the community-based primary care settings in the United States are scarce. Methods. Using a retrospective cohort study design, HCV incidence, defined as HCV antibody seroconversion, was determined in 1147 HIV-infected men receiving care at Chase Brexton Health Care clinics in Baltimore, Maryland between 2004 and 2014. Multivariate regression analyses were used to identify factors associated with incident HCV. Results. There were 42 incident HCV infections during 5242 person-years (PY) of follow up (incidence rate [IR], 8.01/1000 PY). Thirty-seven (88%) of the incident infections were in MSM, of whom 31 (84%) reported no injection-drug use (IDU). The annual IRs for MSM were 13.1-15.8/1000 PY between 2004 and 2007, decreased to 2.7-6.2/1000 PY between 2008 and 2011, and increased to 10.4/1000 PY and 13.3/1000 PY in 2013 and 2014, respectively. Injection-drug use was strongly associated with incident HCV among all MSM (IR ratio [IRR], 14.15; P = .003); however, among MSM without IDU, entering care between 2010 and 2013 (IRR, 3.32; P = .01), being employed (IRR, 3.14; P = .03), and having a history of ulcerative sexually transmitted infections (IRR, 3.70; P = .009) or of polydrug use (IRR, 5.54; P = .01) independently predicted incident HCV. Conclusions. In this cohort of HIV-infected men, a re-emerging HCV epidemic was observed from 2011 to 2014 among MSM. In addition to IDU, high-risk sexual behaviors, favorable socioeconomic status, and polydrug use fueled this increase in HCV infections.
